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Probing hadronic interaction models with the hybrid data of the Pierre Auger Observatory

by Jakub Vícha

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Submission summary

Authors (as registered SciPost users): Jakub Vícha
Submission information
Preprint Link: https://arxiv.org/abs/2209.00744v1  (pdf)
Date submitted: 2022-09-08 09:12
Submitted by: Vícha, Jakub
Submitted to: SciPost Physics Proceedings
Proceedings issue: 21st International Symposium on Very High Energy Cosmic Ray Interactions (ISVHECRI2022)
Ontological classification
Academic field: Physics
Specialties:
  • Gravitation, Cosmology and Astroparticle Physics
Approach: Experimental

Abstract

Presently large systematic uncertainties remain in the description of hadronic interactions at ultra-high energies and a fully consistent description of air-shower experimental data is yet to be reached. The amount of data collected by the Pierre Auger Observatory using simultaneously the fluorescence and surface detectors in the energy range $10^{18.5}-10^{19.0}$ eV has provided opportunity to perform a multi-parameter test of model predictions. We apply a global method to simultaneously fit the mass composition of cosmic rays and adjustments to the simulated depth of shower maximum ($X_\text{max}$), and hadronic signals at ground level ($R_\text{Had}$). The best description of hybrid data is obtained for a deeper scale of simulated $X_\text{max}$ than predicted by hadronic interaction models tuned to the LHC data. Consequently, the deficit of the simulated hadronic signal at ground level, dominated by muons, is alleviated with respect to the unmodified hadronic interaction models. Because of the size of the adjustments $\Delta X_\text{max}$ and $R_\text{Had}$ and the large number of events in the sample, the statistical significance of these assumed adjustments is large, greater than 5$\sigma_\text{stat}$, even for the combination of the systematic experimental shifts within 1$\sigma_\text{sys}$ that are the most favorable for the models.

Current status:
Has been resubmitted

Reports on this Submission

Report #1 by Anonymous (Referee 2) on 2022-10-15 (Invited Report)

  • Cite as: Anonymous, Report on arXiv:2209.00744v1, delivered 2022-10-15, doi: 10.21468/SciPost.Report.5902

Report

I recommend the publication of this contributions after some minor corrrctions are considered.

Requested changes

1 - avoid the use of abbreviations and acronyms in the abstract (X_max, Delta X_max; E_had)
2 - there is a mixed use of are/is and were/was. I would preferably use are/is.
3 - page 2:
** line 3: "using" instead of "by"
** please rephrase more clearly this sentence:"However, the uncertainties on the predicted Xmax scale, hXmaxi, are larger at the energy 10^{18.7} eV than about one third of the difference between the two extremes ". For example: "However, at 10^{18.7} eV, the uncertainties on the predicted X_max scale, hXmaxi, are larger by about one third of the difference between the two extremes..."
** line 2 of Sect. 2: "predictions obtained with" instead of "predictions by"
** line 3 of Sect. 2: remove "to be measured"
** line 4 of Sect. 2: remove "Both"
** line 5 of Sect. 2: remove "Both"
** last 2 lines of the page: I would rephrase. Something like: "This feature suggests to leave both Xmax and Shad free from a zenith angle dependence in the fitting procedure." instead of "From these reasons, we allow in the fitting procedure not only a zenith-angle dependent freedom in the hadronic scale but also a freedom in the simulated Xmax scale."
4 - page 3:
** Caption of fig. 2: "intervals " instead of "bins"
** last line of Sect. 2: add "also" between "is" and "naturally"
** Sect. 3: add "a quantity" between "by" and "Xmax".
** Sect. 3.1: add of before X_max and before S(1000)
** line 5 in Sect. 3.1: "as" (or even "with") instead of "by"
** Sect. 3.2: "perform" instead of "performed"

  • validity: -
  • significance: -
  • originality: -
  • clarity: -
  • formatting: -
  • grammar: -

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